Tool grinding apparatus



Feb. 20, 1951 c, OLIVER 2,542,562

TOOL GRINDING APPARATUS Filed March 22, 1946 4 Sheets-Sheet l Q1 ra 26 4 1 I INVENTOR.

M 1 1 E131: DELIVER L, Y I j l i ii. ATTORNEY Feb. 20, 1951 E. c. OLIVER 2,542,562

TOOL GRINDING APPARATUS Filed March 22, 1946 4 Sheets-Sheet 2 I INVENTOR. 31 gf E1111 DELIVER v BY l U h I I Feb. 20, 1951 Filed March 22, 1946 E. C. OLIVER TOOL GRINDING APPARATUS 4 Sheets-Sheet 5 fITj-E IN V EN TOR.

E1111 DULNER Feb. 20, 1951 E.-CJ-GLIV-ER 2,542,562

T001. GRIND'ING' APPARATUS Filed March 22, 1346 4Sheets-Sheet4 INVENTOR. B111: 13. ULIVBR Patented Feb. 20, 1951 TOOL GRINDING APPARATUS Edd C. Oliver, Adrian, Mich.; Genevieve R. Oliver, executrix of said Edd C. Oliver, deceased, assignor to Genevieve R. Oliver, Adrian, Mich.

Application March 22, 1946, Serial No. 656,330

Claims. (01. 51-97) This invention relates to tool grinders and more particularly to means associated with a grinding machine for grinding or sharpening fluted tools.

The invention comprehends the provision of tool supporting and manipulating means arranged for adaptation with a grinding machine and especially arranged to configurate or resharpen fluted tools having radial or axial relief, or both.

The invention embraces the provision of a tool supporting and manipulating means adapted for use With a grinding machine for configurating or re-sharpening tools such as taps, center drills, gear chamfering cutters and the like which are provided with backing or radial clearance or relief.

The invention has for an object the provision of a tool carrying means adaptable for use with a grinding machine for grinding tools havin both radial and axial relief wherein the arrangement is adjustable to accommodate tools having various pointing angles or taper.

A further object of the invention resides in an arrangement for grinding taps or other tools having axial and radial relief which is adjustable to accommodate various angularities of taper and embodies an adjustable grinding whee1 dressing means whereby the wheel may be dressed immediately prior to a grinding operation.

The invention further comprehends the provision of simple yet effective means for grindin radial clearance or backing upon multi-fiuted tools embodying cam means for actuating the tool into engagement with the grinding Wheel at the proper angularity and simultaneously efiect rotation of the tool to successively grind the operative portions of the tool with the desired radial and axial relief.

Still another object of the invention reside in the provision of means for quickly and effectively adapting the arrangement of the invention to accommodate the mechan sm for grinding tools having varying numbers of flutes.

Another object is the provision of means for dressing the grinding wheel in a zone in substantial alignment with the position occupied by the axis of the tool during grinding operations whereby a high degree of accuracy i obtained.

Another object is the provision of portable unitary mechanism for supporting fluted tools during grinding or sharpening operations which may be used with various'types and kinds of grinding machines.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the re lated elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure 1 is a top plan view of a grinding machine illustrating the arrangement of my invention associated therewith;

Figure 2 is an elevational view of the arrangement of my invention shown in Figure 1;

Figure 3 is an enlarged elevational view of the tool supporting means, parts being broken away for purposes of illustration;

Figure 4 is a sectional View taken substantially on the line 44 of Figure 3;

Figure 5 is a vertical sectional view taken substantially on the line 55 of Figure 3;

Figure 6 is a horizontal sectional view taken substantially on the line 6-6 of Figure 3;

Figure 7 is a disassembled view illustrating elements of an eccentric or cam construction forming a part of the invention;

Figure 8 is a diagrammatic view illustrating an example of the locus of motion of the tool supporting means during grinding operations;

Figure 9 isa front view of the tool supporting means of my invention shown in Figure 3;

Figure 10 is a fragmentary side elevational view of the arrangement of my invention showing the same as utilized for grinding or sharpening a center drill;

Figure 11 is a View similar to Figure 10 showing the arrangement as utilized for grinding or sharpening a gear tooth chamfering cutter;

Figure 12 is a sectional view through the tool actuating cam arrangement showing the method of adjustment,

Figure 13 is a detail sectional view taken substantially on the line I 3! 3 of Figure 6, and

Figure 14 is a sectional view through a tap to show radial relief.

While I have illustrated the arrangement of my invention as particularly adapted for grinding tools such as threading taps, center drills, gear chamfering cutters and the like, it is to be understood that I contemplate the use of my invention for sharpening, configurating or grinding any type of fluted instrumentalities with axial or radial relief.

Referring to the drawings in detail, I have illustrated a portion of a grinding machine including a frame In upon which is supported a hollow housing or casing H in the interior of which is journaled a shaft (not shown). The shaft extends exteriorly of the casing II and supports a grinding wheel I2, the peripheral shape or configuration of which depends upon the type or kind of tool to be operated upon. The rear end of the shaft is provided with a pulle I! which is arranged to be driven by a belt l9 from a motor or other source of power (not shown).

The grinding machine frame is formed with a vertically and revolubly adjustable post 2% having a projecting ledge 2i upon which is mounted a tang 22 forming a sliding bearing for supporting a platen or table 26. The ledge 2i is pro.- vided with a threaded portion (not shown) through which extends a threaded shaft 25-. An unthreaded portion of shaft 26 extendsthrough an opening in a boss 25 carried by the table 25 and is arranged whereby rotation of the shaftZS moves the table 24 longitudinally of the tang or slide 22. Fixed to the end of the shaft 26. is a hand wheel 2! or other suitable manipulating means for rotating the shaft.

The table 2 is formed with a ledge or platform 25 upon which is adapted to be mounted a pedestal or pillow block 36, the lower face of a flange 3! thereof being provided with parallel grooves or keyways within which are disposed keys 32 secured to the member 9 by means of screws 33. The upper surface portion of ledge 29 is formed with a groove 3 adapted to slidably,

receive the keys 32 for permitting adjustment of the member 3G with respect to the ledge 2d. The flange Si is formed with U-shaped recesses or slots adapted to accommodate bolts 35 for fixedly securing member 39 to the ledge 29. Adjustment of the member 39 may be had by releasing the bolts 35 and sliding member 36 along the ledge 29, the member 3% being held in a linear path of movement by means of the keys engaging the grooves or keyways formed in the ledge 29'.

Mounted upon the pedestal 30 is a bracket or support 37 which is integrally formed with a depending cylindrical post or tenon 38 which snugly yet slidably fits into a vertical bore formed in the pedestal. The upper portion of the pedestal 39 is formed with a vertical kerf and joining the portions of the pedestal adjacent the kerf is a, clamping bolt 33. When the clamping bolt 39 is drawn up, the tenon or post 38 is securely clamped against relative movement in the ped- 'estal or block 33. The upper portion of the pedestal 39 is provided with a circular flange or dial portion 40 bearing a series of indicia 4| calibrated to indicate degrees, and the bracket 3'! is provided with an index 42 cooperating with the indicia M on the pedestal to determine the relaative annular position of bracket 31 with respect to the pedestal. The bracket 31' is formed with a projecting ledge 43 supporting a block or abutment 44 which is formed with tenon i extending into an opening in ledge 13, a portion of the tenon 45 being threaded to receive a securing nut 48. The upper surface of the ledge 33' is formed with a key way or rectangular recess 41 into which fits the rectangular lower portion of the abutment 6. The key way serves to maintain the abutment as in a relatively fixed position.

The bracket 37 is formed with a pair of upwardly and outwardly extending spaced ear portions 5!. Each of the ear portions 5! is bored and threaded to accommodate threaded members 52, each threaded member being formed at one end with a cone shaped configuration 53'. Pivotally supported upon the cone shaped configurations 53 of member 52 is a cage or housing 55, the latter having cone shaped recesses to accommodate the pivot members 53. The members 52 are provided at their outer ends with transverse kerfs or slots 57 adapted to receive a suitable tool for adjusting the pivot points 53 to provide for proper pivotal action'of the cage or housing 55 without lateral lost motion between the cage and the member: 31.. Nuts 56; are

threaded on to the members 52 arranged to lock the same in adjusted position.

The housing or cage 55 has an upper semicylindrical portion 663 above which is mounted a semi-cylindrical cap or portion 6|, both portions 60' and 6| when assembled forming a cylindrical or hollow interior configuration arranged to accommodate a tubular member or sleeve 62. The portions 68 and 61 are respectively provided with laterally extending flanges 63 and 64 which are held together by means of securing bolts 65. Bothof portions 60 and El are formed to rovide a hollow configuration or chamber 5? to accommodate a spiral toothed gear 68, the gear wheel 68 having a hub 69 which is drilled and threaded to receive a set screw To which cooperates with a recess in the exterior wall of the sleeve (52 for the purpose of fixedly securing the gear 88 to the sleeve 62. The sleeve 32 is provided adjacent its forward end with an enlarged head portion "H which rests in a suitable circular recess formed in the forward ends of portions to and 61. Surrounding the head portion H is an annular recess formed in portions ti? and 51 arranged to receive and accommodate sealing material 12.

The rear end portion of sleeve 62 is threaded as at 7-3 and is adapted to receive a securing collar 14 which may be adjusted to predetermine the clearance providing for rotation of the sleeve 62 without endwise lost motion. The collar M is adapted to be locked in adjusted position by means of a set screw 16. The sleeve 52 supports a means for carrying a tap, center drill, chamfer cutter or other tool which is be ground or resharpened. Disposed within the forward interior portion of sleeve 62 is a tool carrying member '58 having a bore 90 and which is formed with three slots or keris 19 equally spaced to form a colletlike configuration or chuck. The interior wall of the forward portion of sleeve 62 is tapered as at and the exterior adjacent portion of the chuck or member 18 is reciprocally tapered as at 8| so that when the member '58 is drawn rear- Wardly the cooperating tapered surfaces act to force the jaw portions 82 of member 18, separated by the kerfs 19, into binding engagement with the shank S of the tap T or other tool which is to be ground. The sleeve 52 is bored throughout a portion of its length to a diameter slightly larger than that of the cylindrical portion of member 18 and is adapted to receive a tubular member or inner sleeve 83 which is provided at its outer end with a knurled manipulating knob 84. As shown in Figure 4, the rear portion of member 18 is formed with a threaded tenon portion 85' and the forward portion of sleeve 83 is interiorly threaded for cooperation with the threaded tenon- 85 whereby rotation of the manipulating knob 84 in one direction will draw the member 18 rearwardly into tool clamping or securing position. The side wall of member 13 is provided with a comparatively short keyway 8'! into which extends the head 88 of a pin 89 which is carried in anopening in the side wall of sleeve 62', the member 83- serving to provide for relative longitudinal movement of member T8 and preventing relative rotational movement between member 18 and sleeve 62.

Disposed beneath the sleeve 52 and arranged at an angle with respect to the axis thereof is a shaft 92 which is mounted in cylindrical openings formed in bosses 93 and 94 as shown in Figure 6, boss 93 extending. outwardly from the housing 55while the boss 94 is formed integrally with a cover plate 95' which encloses the rear of cage 55, and is secured thereto by means of suitable screws 96. The shaft 92 is secured in place by means of a set screw 91. Journaled for rotation upon the shaft 92 is a sleeve 98 having a reduced portion 99 formed adjacent one end and upon which is fixed a helical gear I which is in mesh with helical gear 68. The sleeve 98 is also provided with a portion IOI carrying three spur gears I82, I03 and I04 which are arranged in parallel juxtaposed relationship and are arranged to rotate with the sleeve 98 by means of a key I05, the key I 05 also serving to fix gear I00 to the sleeve 98. The gears I02, I03 and I04 are of different diameters for the purpose of changing the relative speed of rotation of gear I00 as hereinafter explained.

The cage 55 is formed with a boss portion I0! and formed on cover 95 is a similarly shaped boss portion I08, both of which are provided'with bores in aligned relation and adapted to receive a shaft H0. Mounted upon the shaft H0 are three gears H4, II 5 and H6 which are spaced apart by means of washers or discs II! and H8 and are in mesh with gears I02, I03 and I04 respectively. While the gears H4, H5 and H6 are journaled for relative rotation upon the shaft I I0, my arrangement includes means for selectively establishing a driving relationship between any one of said gears and said shaft whereby rotation of shaft 8 I0 may be transmitted to shaft 92 to rotate the latter at three different speeds depending upon which of the gears H4, H5 and H6 is in driving connection to rotate with shaft H0. To attain the selective driving connection, the shaft H0 is formed with a slot or recess H9 within which is disposed a latch member I28 which is pivotally supported upon a pivot pin I 2 I, the latter being disposed transversely in a bore in shaft I I0. As particularly shown in Figures 6 and 13, a latch member I20 is provided with a projecting tooth or detent I22 which is arranged to extend into and cooperate with keyways I23 formed in each of the gears H4, H5 and H6. A substantial portion of shaft H0 is axially bored to receive a plunger I25. The plunger I25 has a central axial opening in which is disposed an expansive coil spring I2! and a tenon I28 having a rectangularly shaped head I29. The outer portion of the bore in the plunger I25 is threaded to receive a screw plug I30, the screw plug I30 serving as an abutment or reaction member for the spring I27. The spring I21 serves to urge the head I29 of plunger I 28 into engagement with the latch pawl I28. The latch pawl I 20 is formed with an end surface I3I of such configuration that when the pawl I22 is in engagement with a spline or groove in one of the gears II4,I I5 and H6, the spring I2'I resiliently urges the pawl I22 into selective operative connection with the gear in registration. therewith. The discs H1 and H8 disposed at either side of the centrally positioned gear H5 function to move the pawl I22 out of the keyway or recess of a particular gear when it is desired to shift the pawl to a different gear and to prevent inadvertent disengagement of the pawl from the gear with which it is connected. For example, as viewed in Figure 6, the pawl is in engagement with the recess I23 in gear H6, and if it is desired to connect shaft H0 with gear H5 the operator grasps the knob I26 of plunger I25 and draws the same outwardlytogether with the parts carried thereby including the latch member I20. When the pawl I22 contacts or engages the disc I I8, such engagement slightly rotates the latching member I 22 about its pivot'pin I2I against the action of the spring I21 whereby the pawl I22 slips past the disc H8. As soon as the pawl I22 has passed the disc H8, the expansive force of spring I2'I acts through plunger I28 upon the latching member I20, urging the latter in a direction to move the pawl I22 into the recess I23 formed in gear I I5. This engagement establishes an operative driving connection between shaft H0 and gear I I 5, and simultaneously eliminates the driving connection between gear H6 and shaft H0. By moving the knob I26 further outwardly, the pawl I 22 may, in the manner above explained, be caused to over ride the disc II'I so that an operative driving connection may be established between shaft I I ll and gear H4. Thus by means of the shiftable latching member I20, an effective driving connection may be selectively established between any one of gears H4, I I5 and H6 and the shaft H0 to rotate the driven shaft 90, gear I00, gear 68 and the sleeve 62 at three different speeds for purposes to be hereinafter explained. Additional variant speeds may be obtained by increasing the number of intermediate gears.

Tools such as taps, center drills, chamfering tools and the like are provided with radial and axial relief and are formed with a plurality of longitudinally extending flutes to provide lands having cutting walls or edges. The multiple speeds provided for the sleeve 62 and the collet tool carrier are selectively employed to rotate tools having different numbers of flutes at (lif ferent speeds, the operation of such mechanism being hereinafter explained.

In order to obtain combined or simultaneous axial and radial relief of the tapered portion of the tool, my invention provides for movement of the tool into engagement with the wheel at a particular angle at the same time that the tool and its carrier are rotated through the gearing arrangement hereinbefore described. While any suitable means may be employed for moving the tool into engagement with the grinding wheel, I utilize a cam and abutment means for moving the axis of the tool into the wheel as each land of the tool is being ground or re-sharpened. As particularly shown in Figures 6, 7 and 12, a cam or disc I35 of annular configuration surrounds the shaft H0 and is provided with a central bore I36 of larger diameter than a hub portion I3? formed upon a second disc or member I38. The member I 38 provides a means for carrying or supporting the cam disc I35, the latter being eccentrically or diametrically adjustable about the axis of member I38 and shaft H0. The'disc I38 is formed with diametrically disposed rectangular recesses or slots I40 and disc I35 is formed with diametrically disposed axially extending lugs or ears I42 which are adapted to snugly yet slidably fit into the recesses I40 with clearance in a diametrical direction for adjustment. The lugs I42 are provided with threaded bores radially disposed with respect to the axis of shaft H8 and adapted to accommodate threaded members or screws I44. The bases or bottoms of the recesses I40 are respectively formed with depressions I45 which are adapted to receive the inner extremities of the screws I 44. By manipulation of both of the screws I44, the disc I35 may be shifted diametrically eccentrically with respect to the disc I38 for purposes to be hereinafter explained. The disc I 38 is keyed to the shaft H0 by means of a key I48 extending into a keyway I49 formed in the interior of the heroin disc I38, a set screw I52 serving to fixedly secure the'disc I38 in place 7. to prevent endwise movement. The peripheryor circumferential surface of the; disc I35 engages the upper end surface I50 of the abutment member 44 as shown in Figures 3 and 5. The forward extremity of shaft H is provided with a tenon I55 upon which is mounted a manipulating means or hand wheel I53 which is fixed to rotate with the shaft IIO by means of key I54. An integral projection formed on tenon I55 is threaded to receive a securing nut I55 to hold the hand wheel I53 in position on the shaft. A thrust washer or disc bearing I51 is disposed between the hand wheel I53 andthe boss I01, as shown in Figure 6, to provide durable bearing surfaces.

My arrangement is inclusive of means for truin the grinding wheel I2. The housing 55 is provided with an integral disc-like table portion I60 which is formed with a depending or downwardly extending boss portion IGI, the table and boss portion being bored to accommodate the shaft IE3 which is integrally formed and depends from a member I64, the latter being supported upon the table I60. The shaft I63 terminates in a threaded tenon I65 which is adapted to receive a nut I66 formed with a finger grip I61 to facilitate manipulation thereof in order to clamp the member I64 in fixed position with respect to the table portion I60. The member I04 has a circular disclike portion I63, the periphery of the same being inscribed with a series of indicia 459 representing degrees of angular movement of the table about the axis of shaft I53. The axis of the shaft I63 intersects the axis through the axis of the pivot pins 53 which pivotally support the housing 55. Secured to the table portion I50 isan index or finger I which is adapted for cooperation with indicia on the movable disc I68 for pre-determining the proper angular position of the disc for purposes to be hereinafter explained.

Formed upon the disc I68 is a U-shaped portion including upwardly extending ears I12 which are provided with axially aligned threaded bores to respectively receive a shaft I13 and a shaft I14. As particularly shown in Figure 4, the adjacent ends of the shafts are cone-shaped to present pivot points for pivotally supporting a swingable lever I15, the points of shafts I13 and I14 defining an axis about which the lever I15 is adapted for pivotal movement. The shaft I13 is fixedly secured in position in one of the bosses I12 by means of a set screw I11, while the shaft I14 has a threaded portion adapted to receive a locking nut I18. The outer end of the lever I15 is provided with a laterally extending member I80 which forms a handle for manipulating the lever I15 about its pivotal supporting means. The lever or arm I15 is adapted to carry a grinding wheel truing device or diamond I82 mounted in a'member I83, the latter being received in a suitable bore formed transversely in the arm I15, the truing diamond supporting member being held in fixed position b means of a clamping or set screw I85. The truing operation may be accomplished by swinging the arm I15 upwardly to bring the diamond I82 into contact with the grinding wheel.

The housing cap BI is formed with a pair of upwardly extending ear portions I81 and disposed between the ear portions is an L-shaped member I88 which is pivotall supported by means of a pintlelfiil. The member I88 provides a means of properly positioning or indexing a tap or other tool to be ground in the collet or support 18. The extremity of member I88 is configurated as shown. in Figure 3 to the shape of a thin vane-like portion. I90, the parallel walls of which form locating or positioning means for the tool. One of the walls of vane I engages the wall of a flute in the tap or other tool when the same is of a righthand type, the other wall of the vane being adapted for engagement with the wall of a flute in a tool of the left hand type. By this means there is provided an arrangement for adapting my invention for grinding or shaping taps having either right or left hand threads. The arm I88 may be swung to a position out of use as shown in Figure 2 after a tool has been fixed in position in the collet chuck 18 and before a grinding operation is initiated.

Means are provided for predetermining an initial position of the rotatable sleeve 62in order to afiix a fluted tool in the collet 10' in a proper relationship to be rotated by the gearing in the casing and oscillated by the cam I35 for grinding the several lands of the tool. To this end the cap or housing BI is provided with a boss 200 formed with a vertical bore adapted to receive an indexing or positioning pin 20 I, the upper end of which is provided with a manipulating knob 202. The lower end of the indexing pin 20I has a projecting rectangular pawl or detent 253 which is adapted for cooperation with a kerf or slot 204 formed in the peripheral wall portion of the sleeve 62 to predetermine a starting position for rotation of the sleeve 52.

Means are provided for holding the shaft 20I out of engagement with sleeve 62 during rotative movements of the latter. This means is inclusive of a pin 205 which extends transversely through the member 20 I. The upper face of the boss portion 200 is provided with two sets of diametrically opposed grooves or kerfs 206 and 291 disposed 90 degrees apart. The grooves 200 are of a depth to accommodate the pin 205 so as to lower the member 20I until the detent portion 253 thereof engages in the groove 204 to secure the sleeve 52 in fixed position for initial setting of the tan or tool preparatory to grinding operations. When rotation of sleeve 62 is to take place, the member 20I is elevated by means of the finger piece 202, and the assembly rotated through 90 degrees until the pin 205 is in registration with the shallow recesses 201 as shown in Figures 2 and 3. Engagement of pin 205 in the shallow recesses elevates the detent 203 above sleeve 62 so that the latter is free to rotate.

The operation of the arrangement of my invention is as follows: When it is desired to grind or sharpen a tool as for example, a tap T, the tap is first fixed in a particular position in the collet or supporting means 18. The finger piece 84 is rotated by the operator in a direction whereby the collet member 18 is moved to its forward position with the jaws 82 sprung outwardly. This action permits the shank S of the tap T to enter the hollow interior or bore 90 contained in the collet member. The sleeve indexing member 202 is rotated so that the detent 203 will be in a position to fall into registration with the kerf 204 so as to properly index the sleeve 62. The hand wheel I53 is then rotated, and through the medium of the gearing contained in the housing 55, the sleeve 62 is rotated until the detent 203 engages in the kerf 204. The operator then swings the L-shaped member I88 from its out-of-use position as shown in Figures 1 and 2 to the tap locating position shown in Figure 3.

The tap or tool T is then rotated by the operator until one wall of the land thereof, formed by the fluting in the tool, engages. the projection or 10-- tatm poruon I90 of member I88. This engagement establishes or predetermines the position of the tap circumferentially in the collet I8 so as to establish a proper relationship between the tap and sleeve 62. The operator then grasps the finger piece 84 and rotates the same in a direction to thread the inner sleeve 83 onto the threaded end of the collet member I8, which action draws the jaws 82 of the collet member I8 tightly into engagement with the shank S of the tap T. The L-shaped member I I8 is then swung to an out-of-use position as shown in Figures 1 and 2, and the indexing member 202 elevated to disengage the detent 203 from the kerf 204 in the periphery of sleeve 62. In elevated position, the member 202 is rotated so that the pin 205 rests in the shallow recesses 20! so as to maintain the detent 203 out of engagement with the sleeve 62. The foregoingoperations position thevtap in the support fixture.

The bracket 37 is adjusted by rotating the post 35 in the pedestal or support 30 to set the tap at the proper angle for engagement with the peripheral face of a grinding wheel I2 to secure the desired pointing angle or tool taper. The angular position of the bracket 31 and hence the tap supporting means may be determined by the indication provided by the indicia 4|. After the proper angular relation is established, the bolt 39 may be drawn up to tightly clamp the post 38 in the pedestal 30.

To insure accuracy in grinding, it is desirable to dress or true the grinding wheel prior to the grinding operations. In accomplishing this operation, the bracket IE4, pivotally supporting the lever I15 and carrying the dressing diamond I82, is. adjusted about a vertical axis by shifting the post I63 in a bore in the boss member I6I carried by the housing 55, the angle of rotation being determined by the indicia in registration with the index member I75. By this means the wheel dressing tool may be adjusted for swivel movement about the axis of the pivot pins I13 and I14 so that the wheel may be dressed in the proper angle with respect to the position of the tap or other tool carried in the collet 18. After the bracket I64 carrying lever I75 is adjusted to the proper angle, the lever I I5 is swung upwardly to bring the diamond point I82 into engagement with the peripheral face of the grinding wheel causing the latter to be abraded at the proper angle.

As the arrangement of my invention is adapted to grind both axial and radial or backing relief upon the tap or other tool, the cage or housing 55 and tap mounting means are arranged for movement about the axis of the pivot pins 53 to move the tap into contact with the wheel in an arcuate locus. This is necessary in order to obtain relief or backing off clearance for the lands of the tap as illustrated at R in Figure 14. After the wheel has been dressed in the manner above explained, the tap T and the mechanism hereinbefore described carried by the bracket 31 are arranged to be moved toward the wheel I2. This movement is obtained by rotation of the hand wheel 21. When the tap is brought in juxtaposition with the grinding wheel, the operator rotates the hand wheel I53 thus rotating the cam I35 and driving shaft III]. Rotation of shaft H will cause rotation of sleeve or bushing 98 at a speed dependent upon which of gears H4, H or I I6 is connected to be driven by shaft I it! through the medium of the latch member I carrying the driving pawl I22. If the fluted tool or tap is a. 10 provided with four flutes, the gear H4 is connected by pawl I22 to be driven by shaft H0. This selective driving engagement is obtained by moving the latch member I20 by manipulating the knob I26 axially of the shaft Ill). If the fluted tool is provided with three flutes, the gear H5 is connected by the pawl I22 to be driven by shaft H0, and if the tool is formed with two flutes the gear I I6 is placed in driving connection with shaft H0. Thus the gear III] will drive the gear 88 and hence the sleeve 62 and the tap carried by the collet I3 at a speed with respect to the cam I35 dependent upon th number of lands or flutes in the tool.

The amount or degree of radial and axial relief or clearance is dependent upon the amount of eccentricity or adjustment of cam I35 with respect to the axis of disc I38 and shaft III]. The amount of eccentricity of the cam or disc I35 determines the magnitude or amount of forward movement of the housing 55 about the supports 53. The degree of eccentricity of the cam may be regulated or varied, and hence the clearance or relief angle for the tap changed, by adjusting the screws M4 carried by the projections I42 formed on the cam member I35. The oscillatory movement of the housing 55 about its pivotal axis is caused by rotation of cam I35 in engagement with the upper surface I 58 of the abutment 44. The operator rotates the hand Wheel I53, thus rotating the cam or eccentric I35, and with each elevational movement of the housing 55, a land of the tap is ground with radial relief or clearance as well as with axial relief, the tap being continuously slowly rotated whenever hand wheel I53 is rotated. As the housing 55 recedes from the grinding wheel by pivotal movement in a counterclockwise direction witheach descending cycle of the cam, as viewed in Figure 3, the tap T being rotated continuously by rotation of the sleeve 62 is brought into position for the next succeeding land thereof to engage the grinding wheel. Upon the next successive oscillatory movement of housing 55 caused by the action of cam I 35, the succeeding land of the tool is ground with radial clearance or relief. This cycle is repeated until all of the lands on the tool have been brought into engagement with the grinding wheel. Between each complete grinding of the several lands of the tool, the entire grindin fixture may be readjusted by movement of the fixture support or table 2d toward the grinding 'wheel' preparatory to repeating the cycle of grinding operations for further grinding of the tap if the condition of the tap requires additional grinding.

Figure 8 illustrates diagrammatically the direction or locus of movement of the tool carrying means. The line AB in this figure represents the axis of oscillation of the housing 55 through the pivot pins 53 and the line CD represents the axis of the tool when carried in the chuck I8 associated with the sleeve 52. The line OD represents the component or vector of movement of the tool toward o into the wheel and represents axial relief while the line HD represents the component of radial relief. The line OH is the resultant component representing the compound movement of the tool into the wheel whereby combined axial and radial relief is obtained simultaneously. Thus it will be noted that the tool moves into the grinding wheel generally in a longitudinal direction, the tool continuously rotating simultaneously with its movement into '11 the wheel whereby compound radial and axial relief is obtained simultaneously,

Figure of the drawings illustrates the arrangement of my invention as used for grinding or sharpening center drill 210. It is to be noted that the grinding wheel 12 has a peripheral shape or configuration to produce the exterior contour of the center drill during grinding operations. The axial and radial relief is imparted to the center drill in the same manner that is utilized in obtaining the relief in a tap.

Figure 11 illustrates the arrangement of my invention as utilized for grinding a chamfering cutter I22 with both axial and radial relief. In grinding this type of tool it should be noted that the grinding wheel 12" is configurated so as to obtain the proper silhouette or exterior contour of the cutter.

While I have illustrated the arrangement of my invention as particularly adapted for imparting axial and radial relief to taps, center drills and chamfering tools, it is to be understood that I contemplate the use of the arrangement for any other type of tools wherein radial relief, axial relief or both are to be imparted to any tool or instrumentality. The fixture may be used with any suitable type of grinding machine, the drawings illustrating in part one form with which the fixture is particularly adaptable.

It is apparent that, Within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What I claim is:

1. In a tool grinding apparatus comprising in combination, a pedestal; a bracket associated with said pedestal and arranged for rotary adjustment with respect thereto; a housing pivotally supported upon said bracket and arranged for oscillation about the axis of said pivotal connection; a tool holder journaled for rotation-upon said housing about an axis angularly disposed with respect to the axis of pivotal movement of the housing; means for rotating said tool holder relative to said housing; and means associated with said tool rotating means for causing oscillation of said housing about the axis of its pivotal support; and means for varying the number and amplitude of oscillations of said housing with respect to the rotational speed of said tool holder.

2. An apparatus for mounting tools during grinding operations comprising in combination, a support; a bracket revolubly mounted upon said support; means for locking said bracket in adjusted position upon said support; a housing mounted upon said bracket and arranged for relative oscillatory movement; a driving shaft journaled on a housing; a plurality of gears of different diameters mounted on said driving shaft; a member journaled on the housing; a plurality of gears mounted on said member and in enmeshment with the gears journaled on said driving shaft; a tool supporting member journaled upon said housing and arranged to be driven by said gearing about an axis angularly disposed with respect to the axis of oscillation of the housing, and means for establishing a selective driving connection between sets of said gears for varying the speed of said tool supporting member with respect to said driving shaft.

3. An apparatus for mounting tools during grinding operations comprising, in combination, a support; a bracket revolubly mounted upon said support; means for locking said bracket in adjusted position upon said support; a housing mounted upon said bracket and arranged for relative oscillatory movement; a driving shaft journaled on the housing; a plurality of gears of difierent diameters loosely journaled on said driving shaft; a member journaled on the housing; a plurality of gears fixedly mounted on .said member and in enmeshment with the gears journaled on said driving shaft; a tool supporting member journaled upon said housing about an axis angularly disposed with respect to the axis of oscillation of the housing and arranged to be driven by said gearing means for establishing a selective driving connection by said driving shaft and the gear journaled on said shaft for varying the speed ofxsaid tool supporting member with respect to said driving shaft.

4. In a tool grinding apparatus including in combination, a support; a bracket mounted on said support and arranged for rotary adjustment with respect thereto; a housing supported upon said bracket and arranged for oscillation about an axis; a tool holder journaled on said housing for rotation about an axis angularly disposed with respect to the axis of oscillation of the housing; means for rotating said tool holder; means associated with the tool holder rotating means for oscillating said housing about its axis; means for varying the amplitude of oscillatory movement of the housing, and means for varying the frequency of oscillations of the housing with respect to the rotational speed of the tool holder.

5. In a tool grinding apparatus including in combination, a support; a bracket mounted on said support and arrangedfor adjustment with respect thereto; a housin supported upon :aid bracket for oscillatory movement relative thereto; a tool holder journaled on said housing for rotation about an axis angularly disposed with respect to the direction of oscillation of said housing; means including gearing for rotating said tool holder; means associated with said tool holder rotating means for concomitantly oscillating said housing relative to the bracket; means for varying the amplitude of oscillatory movement of the housing, and means for varying the frequency of oscillations of the housing with re-- spect to the rotational speed of the tool holder.

EDD C. OLIVER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 641,107 Heister Jan. 9, 1900 704,348 Lapointe July 8, 1902 762,838 Norton June 14, 1904 1,016,891 Mill et a1. Feb. 6, 1912 1,231,720 Drake July 3, 1917 1,553,522 Durkee Sept. 15, 1925 1,813,682 Shriver July 7, 1931 2,046,261 Green June 30, 1936 2,056,149 Griffing Sept. 29, 1936 2,209,228 Judge July 23, 1940 2,350,234 Horton May 30, 1944 2,413,436 Dawson Dec. 31, 1946 2,430,423 Heim Nov. 4, 1947 

